From f1d9a2abff66aa8156fbc1493abed468db63ea48 Mon Sep 17 00:00:00 2001 From: Miroslav Benes Date: Sat, 25 Apr 2020 05:03:07 -0500 Subject: x86/unwind/orc: Don't skip the first frame for inactive tasks When unwinding an inactive task, the ORC unwinder skips the first frame by default. If both the 'regs' and 'first_frame' parameters of unwind_start() are NULL, 'state->sp' and 'first_frame' are later initialized to the same value for an inactive task. Given there is a "less than or equal to" comparison used at the end of __unwind_start() for skipping stack frames, the first frame is skipped. Drop the equal part of the comparison and make the behavior equivalent to the frame pointer unwinder. Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Reviewed-by: Miroslav Benes Signed-off-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/7f08db872ab59e807016910acdbe82f744de7065.1587808742.git.jpoimboe@redhat.com --- arch/x86/kernel/unwind_orc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 45166fd50be3..e9f5a20c69c6 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -657,7 +657,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, /* Otherwise, skip ahead to the user-specified starting frame: */ while (!unwind_done(state) && (!on_stack(&state->stack_info, first_frame, sizeof(long)) || - state->sp <= (unsigned long)first_frame)) + state->sp < (unsigned long)first_frame)) unwind_next_frame(state); return; -- cgit v1.2.3